Re: Linux DMA address

On 7/2/2012 2:44 PM, Klaus Wacker wrote:

[...] So whats the nature of the returned DMA address of ib_dma_map_single and can we
assume that it is the same value on different devices on one system?

Currently, over all IB drivers/devices except for ipath and qib, 
ib_dma_map_single is just plain dma_map_single, so your questions 
relates directly to the Linux DMA mapping API (and BTW - the answer is 
YES, in the general case you must use a DMA address you were provided 
when calling dma_map_single with device being X only for transactions 
carried over X). For those devices that hack ib_dma_map_single, it might 
be possible to use address provided from device X over device Y, but 
this is a hack, and I would strongly recommend not to have it in you code.

Or.
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